This invention relates to an ensemble and method for protecting the wearer from the adverse effects of acceleration, such as is encountered in high performance aircraft.
Pilots in high performance aircraft are subjected to substantial accelerations or "G-loads" while maneuvering their aircraft. These accelerations can cause the blood to drain from the pilot's head and pool in the lower portions of the body, resulting in diminished peripheral vision, as well as dizziness, unconsciousness, and even death. The amount of G-loading the pilot can withstand is often a limiting factor in the design of the aircraft.
To counter-act the effects of G-loading, pilots sometimes engage in straining maneuvers, tensing the muscles in the lower portion of the body to reduce blood pooling. However, such measures are only temporary, are physically fatiguing, and are ineffective against high G-forces. Various attempts have been made to protect pilots from these accelerations or G-loads.
One method involves reclining the pilot when G-loads are applied. Reducing the vertical height of the pilot reduces the pressure differential in the body, reducing the tendency of the blood to pool in the lower extremities. See for example McGrady et al., U.S. Pat. No 4,787,576.
Pressure suits have been made which have a plurality of air bladders that can be filled to compress the blood vessels in the lower portions of the body to maintain the blood flow to the wearer's head. See, e.g, Van Patten, U.S. Pat. No. 4,736,731; Krogh et al., U.S. Pat. No. 4,638,791; Crosbie et al., U.S. Pat. No. 4,534,338; Crosbie et al., U.S. Pat. No. 4,243,024; Beaussant et al., U.S. Pat. No. 4,230,097. The air bladders cannot stay inflated, however, because they decrease the normal blood flow to the lower parts of the body. There is a built in delay in the response of this type of suit to the G-loading, as the suit is inflated in response to applied G-loading. Moreover, these suits usually are incapable of applying a counter pressure proportional to the pressures generated in the blood vessels by the G-loading, and thus they do not exactly counterbalance the applied G-load so the wearer usually experiences some of the affects of the G-loading.
Anti-G suits have also been made that surround the wearer, or parts of the wearer, with a column of fluid. See for example Holste, U.S. Pat. No. Re 22, 01; Beall, U.S. Pat. No. 2,335,474; Gray, U.S. Pat. No. 3,089,482; Congwer, U.S. Pat. No. 3,137,290; Kops et al., U.S. Pat. No. 3,124,123; Beaussant, U.S. Pat. No. 4,546,491; and Wurst et al., U.S. Pat. No. 4,925,133. The fluid provides a hydrostatic pressure to the wearer in proportion to the height of the column and the applied G-load. This type of suit provides continuous and instantaneous response to G-loading. However, these suits are extremely difficult to put on and take off, and once they are on, they are very heavy and cumbersome. Moreover, once in the suit, the wearer's movement is severely restricted. The wearer often needs assistance into and out of the aircraft. ln some cases, special supports must be provided to support the wearer in the aircraft. Many of these suits require an external reservoir to accommodate fluctuations in the volume of liquid in the suit from G-loading, from simple body movement, and even from breathing. This may require that a special fluid reservoir be provided in the aircraft. The wearer of the suit must connect the suit to the reservoir upon entering the aircraft and disconnect the suit from the reservoir upon leaving the aircraft.